Heretofore, in large size rotary hydraulic actuators of the character indicated the main unit has included the trunnions as an integral part thereof and hence it was necessary for shipment to detach the power pack and the pairs of hydraulic cylinders and piping on opposite sides of said unit and to send the manufacturer's personnel to the shipyard or other location to reassemble the hydraulic cylinders and piping and power pack onto said unit thereby entailing substantial additional expense and highly skilled labor.